Engine vibration

[IncaDolly78]

Hi I've recently replaced the engine mounts & stabilzer mount on the Sprint but have found a it has a nasty vibration now, particularly on tickover. The clutch was recently replaced but due to a slight continuing shudder on pull away I was told replacing the mounts might help. Old mounts were certainly perished.
would lifting the engine up 1-2" to replace the mounts have damaged something? I loosened the far rear mount which the gearbox sits on before lifting the engine.

Any suggestions would be helpful, thank you.

[Mad Mart]

Did you refit the mounts on their correct sides? with the semi-circular cut outs upwards & towards the front?

[IncaDolly78]

Thanks for your reply, I think they're the right way round as I checked before re-fitting and compared to old mounts. I'll double check tomorrow in daylight though.

[gmsclassics]

If the gearbox mount gets soaked in oil it can become very soft and cause the symptoms you describe. However you should be able to see this at tick over with the bonnet raised - there will be a lot of movement at the back of the engine, more so than at the front. Last one I had to change I wrapped in a plastic bag so the oil couldn't get to the rubber! Of course I could have fixed the leak!

Geoff

[Jon Tilson]

If you still have the old ones I would consider putting them back, depending of course how old they are and what sort of condition
and where and how old the new ones are.

Anyway it seems you have nothing to loose by going back, if all you originally had was mild clucth judder.

There were quite a few variations of hardness available way back when we were younger and Sprints were newer.
Quite a few of us were fobbed off with uprated ones which generally lowered the refinement and moved stresses to where they shouldnt be moved.
Said new and uprated ones were of variable quality. I've long since given up on anything that purports to be uprated and sold by large northern concerns
as bin fodder. They often come away from the metal backing within months.

I've got a box of Sprint engine mounts that I occasionally need to use if a car comes in with a broken or suspect one. Some of them have a number which I presume
is something to do with the "shore" rating. As Mart says you need to fit them the right way up AND on the right side of the car. I've seen all possible combinations of wrong
fitting in cars that come in, some result in the engine sitting too high and marks on the underneath of the bonnet. On one car I had in one of the mounts had been butchered
so the engine sat at the wrong angle and the downpipe touched the subframe, so there was some interesting vibrations and resonance. I've rarely had such a simple fix
make such a big difference.

The steady bar rubbers are pretty much the same as shock absorber ones. I've raided a few cheap shock bush kits or even my old "spare" shocks for these on more than one occasion. They do suffer a bit from the exhaust manifold heat. I usually loosen them off after a new engine fot has "settled" a bit then tighten them up again. You need to look at parts book pics to see you have all the various slotted sqaure washer bits and bobs so this works as intended. Quite a few have bits missing.

I strongly suspect that your clutch judders are down to axle tie bar bushes. So you have a mild case of axle tramp which is easy to mistake for clutch judder. The ones
at the axle end tend to suffer and if they get soggy this will cause your problem.

The gearbox mount can be a suspect but only if its old or soaked in oil. Again beware of the replacements because some are meant for TR8's and SD1's and dont have
the right characteristics for a dolomite.

Good luck.

Jonners

[Reg]

I went back to my old mounts, the remanufactured ones I bought were way, way too rigid! So rigid in fact, they wouldn't line up with the location holes on the subframe!

I got out of my "I've gotta buy new all the time" b/s way of thinking, pretty damn quick because of crap remanufactured parts from certain companies..

Another one, was the remanufactured choke cable that I ordered, it turned out to be four inches short..

[IncaDolly78]

Thank you all for your replies... interesting. Fortunately I have a parts catalogue so I am in the process of checking all the fitments are correct. I note the o/s and n/s from the book that the brackets are different, it looks like the offside is shallower than the nearside one? I replaced them one at a time so they're back on the sides I took them off but of course I shouldn't assume they were correct in the first place! They seem to be fitted the right way up at least as the semi-circular cut out is at the top / front on both sides.
Looking at the stabilzer bar fitting, I seem to be missing the locking channel (part no 159381), which sits under the main bracket, maybe I've lost that... looks like it may help reduce sideway movement of the engine. A couple of washers are missing too but the bushes seem fitted ok, they're polybush and from Rimmers (sorry about the swearing haha!). One of the mounts came from them too, the other mount was "new" from an auto jumble. I think I'll try to get the stabiliser bits sorted, look for rear engine movement on tick over and if all ends fails put the old mounts back on, just to see if that helps. They are pretty perished though!

Will update!

Thanks

[Jon Tilson]

See how much the old and new ones twist by hand. They can look pretty perished on the outside but
are probably ok if not soaked in oil.

Sounds like you have them on right.

Jonners

[IncaDolly78]

Amazingly I managed to find the locking channel, wrapped up in a little bag, first time ever I've found something that was mislaid! Stabiliser bar all re fitted and tight, vibration seems less but I wonder if the mounts are too stiff and have no give in them. I need to take it out for a run really before knowing if it's much better.

As suggested I might put the old mounts back on to soften things up a bit!

Thanks.

[dursley92]

I went back to my old mounts, the remanufactured ones I bought were way, way too rigid! So rigid in fact, they wouldn't line up with the location holes on the subframe!

I have just put old mounts back on my Sprint engined TR7 for just the same reasons. The new remanufactured ones were much too hard and caused quite a bit of annoying vibration. Might be OK for competition use but not acceptable on a road car.

[IncaDolly78]

Interesting that several people have similar experiences re vibration. I wonder if there's any NOS mounts anywhere!?

[SGde3a]

It sounds like the best thing to do is to soak ALL the mounts in oil to soften them up. Might try this in the next few days. Vibration is nasty but also have the polyeurethane subframe bushes.